Two homologous radioimmunoassays for bovine follicle stimulating hormone (bFSH) were utilized in comparing the differential regulation of FSH and luteinizing hormone (LH) in response to ovariectomy or administration of gonadal steroids in cattle. There appeared to be significant LH cross-reactivity in one of the bFSH systems (bFSH-HS-2-17), but not in the other (bFSH-BP3). Concentrations of FSH...

The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH ente...

INTRODUCTION The objective of this study was to investigate the frequency of lipohypertrophy (LH) and the associated risk factors in young patients with type 1 diabetes mellitus (T1DM). METHODS This cross-sectional study was conducted on a sample of 174 patients with T1DM (aged 13-18 years) treated with multiple daily insulin injections for a minimum duration of 1 year. The study was performe...

The aetiology of polycystic ovary syndrome (PCOS) is unknown. It is uniquely characterized by oligomenorrhoea or amenorrhoea associated with normal or high oestrogen levels. This prospective clinical study was designed to examine the possible role of the lack of cyclical exposure to progesterone in the development of gonadotrophin and androgen abnormalities in PCOS. Gonadotrophin, androgen and ...

Luteinizing hormone (LH) administered in pharmacological amounts downregulates Leydig cell steroidogenesis. Whether reversible downregulation of physiological gonadotropin drive operates in vivo is unknown. Most of the analytical models of dose-response functions that have been constructed are biased by the assumption that no downregulation exists. The present study employs a new analytical pla...

Interest in negative refractive index, or left-handed (LH) materials, has escalated rapidly over the last few years and it now appears that useful LH materials may be realizable in the microwave region. However there is also considerable interest in LH materials for infrared and visible applications. The purpose of this paper is to explore the limitations of LH materials at short wavelengths du...

The gonadotropin-ovary axis of patients with anorexia nervosa was assessed with the aim of distinguishing between an intrinsically hypophysial deficiency and pituitary malfunction secondary to hypothalamic impairment. The most consistent endocrine abnormality was low serum luteinizing and follicle stimulating hormone (LH and FSH) levels associated with depressed serum estradiol levels. Gonadotr...

Pancreatic carcinoma is one of the cancers with the worse prognosis, thus any therapeutic improvement is imperative. Cytotoxic LH-RH analog, AN-152 (proprietary designation, AEZS-108), consisting of doxorubicin (DOX) conjugated to D-Lys⁶LH-RH, is now in clinical trials for targeted therapy of several sex hormone-dependent tumors that express LH-RH receptors. We investigated LH-RH receptors in h...

The response of steroidogenic tissues to tropic hormones is regulated in part by specific receptors in the target cells for the stimulatory hormone. As a result of hormone binding to receptor the enzyme adenylate cyclase is activated with a resultant increase in intracellular levels of cAMP. Enhanced protein kinase activity then leads to increased steroidogenesis via several possible mechanisms...

Twenty-two mature pluriparous beef cows were randomly assigned to one of six treatments in a 2 X 3 factorial experiment in order to study the role of suckling and ovarian factors on control of the tonic and episodic release of luteinizing hormone (LH). Twelve cows remained intact (INT) and 10 were ovariectomized (OVX) within 4 days following the day of parturition (Day 0). The suckling intensit...